Locomotive boiler



1929- P. THOMSEN LOCOMOTIVE BOILER Filed April 20, 1923 2 Sheets-Sheet A TTORNEKS' Uct. S, 1929 P. THOMSEN LOCOMOTIVE BOILER Filed April 20, 1923 2 Sheets-Sheet 2 m/mvm/a ErE/e pmMsE/v ATTORNEYS HUT/V558 Patented Oct; 8, 1929 UNITED STATES PATENT- OFFICE PETER. THOMSEN, OF CASSEL, GERMANY, ASSIGNOR T SCHMID'IJSCHE HEISSDAMPF GESELLSCHAFT M. B. H., OF CASSEL-WILHELMSHOHE, GERMANY, A CORPORATION 01' GERMANY LOGOMOTIVE BOILER Application filed April 20, 1923, Serial No. 633,413, and in Germany April 22, 1922.

My present invention relates to locomotive boilers and particularly to an improved construction of the fire-box thereof, embodying water tubes which are exposed to the combustion gases and thus adapted to produce steam. Fire-boxes with Water tubes are well known in the art and a type customarily employed is known as the Brotan fire-box. This type is open to the serious objection that after lo a relatively short period of operation the water tubes become obstructed by boiler scale and will then burn out. The reason for this detrimental behavior is that the water tubes of the Brotan fire-box are relatively wide and 15 therefore the circulation of water through them is rather poor and slow. On account of the limited space available in locomotive engines the water receptacles or mud drums which connect with the lower ends of the so Brotan tubes can be made only of a limited cross section, which in many cases is as little as one-twelfth of the cross section. of the Brotan tubes themselves. From this it will be evident that there can be no active circulation as from the boiler to the mud drums and from them'baci: to the boiler through the Brotantubes. Owing to the relatively slow flow of the water, boiler scale and mud are not can ried to the main boiler but will become deposited on the walls of the Brotan' tubes and particularly in the mud drums or water chambers located at the bottom. When high boiler pressures are employed, such as. pressures above 20 atm., this drawback is accentuated e5 since the small bubbles of steam generated in the Brotan tubes are not of suflicient size to enable them to carry large amounts of water with them upwardly. Furthermore the relatively thick Brotan tubes are so rigid as to 40 often become leaky at the joints.

. In another type of water tube fire-boxes for locomotive boilers employed hitherto the walls of the fire-box were formed by relatively narrow tubes connected with steam collectors located above the fire-box. In this construc- "the Brotan fire-boxes, that is to say, the circulation of water is not efficient. Since in this earlier construction the descending tubes are connected with the ends of the steam collectors, these water tubes which are situated near the center of the fire-box will receive too small a proportion of water since they are farthest away from the said descending tubes. With this earlier construction therefore the relatively cold water discharged from the de seending tube's cannot be distributed uniforml and perfectly among theseveral water tu es but such cold water will be received chiefly, if not exclusively, by these water tubeswhich-are nearest to the descending tubes. In consequence thereof the water tubes drying at a distance from the connection with the descending tubes, and receiving no water from said descending tubes or only an insuflicient supply of cool water, will not be cooled sufficiently and are therefore liable toburn out.

My present invention provides a means of avoiding the objections indicated above and embodies a fire-box having inner water tubes fitted into mutual contact in such a manner as to form a continuous or closed Wall which 7 thus acts as a shield to protect a group of outer tubes from contact with and heating by, the combustion gases. The inner: tubes carry the water and steam upwardly while the outer tubes carry the relatively cool waterdownwardly. This inner group of tubes may be formed by bending two sets of tubes into a common plane or by tubes having fins or ribs. The upper ends of the descending tubes may be connected with the collector receiving steam from the inner generating tubes. Ac- 90 cording to one form. of my present invention these descending tubes are connected with water chambers separate from the steam collectors of the inner generating tubes and communicating with the main boiler of the locomotive. In this particular form of my invention, therefore, the main boiler is interposed in the path of the water from-the gen erating tubes to the descending tubes.

Among the numerous important advantag-es of my invention I desire to emphasize the following: i

The generation of steam is great owing to the relatively small diameter of the generating tubes; even small steam bubbles are able to carry with them considerable amounts of water. lhe supply of cool water .is very abundant owing to the fact that adjacent to the generating tubes there is a large number of descending tubes supplying relatively cool water; the number of descending tubes may be equal to the number of ascending steam generating tubes- Furthermore there is a uniform distribution of the water issuing from the descending tubes, among the ascending generating tubes, for the reason that the cool water issuing from one descending tube finds its way to one or more ascending tubes located in the immediate vicinity of the dis: chargeend of such descending tube. In that species of my invention in which the chambers supplying relatively cool water to the upper ends of the descending tubes are separate from the chambers or collectorsconnected with the upper ends or the steam generating tubes, there is a very active circulation of water through the main boiler. By this arrangement I prevent the accumulation of boiler scale in the steam generating tubes, in the lower water chambers, and in the collectcrs connected with the steam generating tubes.- The relatively rapid flow of water carries all these deposits from the dangerous region of the generating tubes and of the steam collector, to the main boiler. The lower water chambers of: the lire-box can be made very small owing to the provision of narrow and numerous descending tubes and this enables me to place fire-boxes with a suihcient grate area even between the driving wheels of a locomotive so that my invention may be readily applied to express passenger locomotives. The use of tubes and of water chambers of relatively small diameter in connection with the fire-box gives the latter a considerable elasticity so that -leaks, which are quite frequent with the usual Brotan fire-boxes, will become very rare with my improved construction. Several con-- structions embodying the principles of my invention are illustrated in the accompanying drawings in which Fig. 1 is a cross section and Fig. 2 a longitudinal elevation in diagrammatic fashion showing a locomotive boiler constructed according to my inven tion; Figs. 3, 4: and 5 are detail vertical sections upon an enlarged scale showing various soecific ways of connecting the lower ends or the ascending and of the descending tubes with the water chambers at the sides of the grate, and Figs. 6, 7 and 8 are horizontal sections on the correspondingly numbered lines of Figs. 3, 4E and 5, respectively.

In Figs. 1 and 2, A designates the longitudinal boiler of the locomotive; B the steam collector which communicates with said boiler; C are the inner water tubes or steam generating tubes which are located in two groups or sets at opposite sides of the firebox; D are the descending water tubes which carry the relatively cool water to the water chambers E located at the sides of the firebox and also connected with the lower ends of the steam generating tubes C, and G is the grate located between the two sets of steam generating tubes C and between the two water chambers E. At the left-hand side 0)": Fig. 1 the upper ends of the descendin tubes D are shown connected directly with the steam collector B, as are also the upper ends of the ascending steam generating tubes C. At the right-hand portion of Fig. 1 l have shown the upper ends of the descending tubes D connected with a water chamber F. separate from the collector B and communicating with the main boiler A of the locomotive. While 1 have shown the left-hand portion of Fig. l and the right-hand portion thereof as of unlike construction, it will be understood that both portions might be constructed alike and in practice this will be preferred. The tubes (3 are set or arranged in such a way as to constitute a continuous wall and therefore the combustion gases will be confined between the two walls so formed and the descending tubes D which are located exterior-1y or" such walls, will be shielded and thus remain relatively cool so that the efliciency of the cir-,

culation will be greatly increased. The tubes C being relatively narrow, the generation of steam in them will proceed very energetically and rapidly and the steam bubbles will carry with them large amounts of water into the upper drum or collector B. The relatively cool water will flow from said collector B back to the lowest water chambers E and it will be noted that the tubes D are distributed along the entire length of the said water chambers E so that a uniform distribu tion of the returning relatively cool water is eflected among all the ascending steam generating inner tubes 0. Those tubes D which are connected with the upper collector B enters the same not only at the ends, as in certain prior constructions referred to above, but at different points along its length thereby also insuring a better circulation of the water. Similarly when the upper'ends of the tubes D are connected with a separate water chamber as indicated at F at the righthand portion of Fig. 1, such tubes are connected with said separate chamber at difier- .ent points of its length and not only at the ends.

For the purpose of forming a practically continuous wall or shield by means of the ascending steam generating tubes C, various specific constructions may be employed. For instance, as illustrated in Figs. 4 and 7, there may be twice as many tubes C as there are tubes D and certain tubes 0 may be in line with the adjacent tubes D While the intermediate tubes (indicated at C) have their lower ends staggered by bending them to one side at points between two adjacent tubes D. This arrangement enables me to employ a large number oi ascending tubes C without unduly weakening the upper wall of the water chamber E. Instead of this arrangement in which neighboring tubes of the inner wall are in direct contact, I may adopt arrangements in which such inner steam generating tubes C are provided with flanges or extensions in mutual contact. In one such arrangement illustrated by Figs. 3 and 6, the tubes C are provided with lateral flanges H at the side nearest to the set of outer tubes D and the surfaces of said flanges which face the tubes D are preferably plane and flush with one another so as to constitute a practically continuous surface. It willbe understood that Figs. 3 to 8, inclusive, illustrate the left-hand water chamber E and its connections. There fore, in Figs. 3 and 6, the tubes C are exposed to the action of the combustion gases on considerably more than one-half of their peripheral surface and the flanges H not only serve to close the fire-box space but also conduct the heat to the exterior portions of the tubes C so that the latter are efiiciently heated at practically all points of their corcumference. At the same time, since the outer surfaces of the flanges are flush with each other and form part of the same plane, the radiation of heat towards the tubes D is minimized and the heating eifect on the tubes C therefore made aslarge as possible. The fact that the heat is conducted from the ribs H to the water in the tubes C, contributes to cool the said ribs to a certain extent and thereby protects them against being burned out. Another construction with flanged inner tubes D is shown in Figs. 5 and 8. Here the tubes C are staggered relatively to the tubes D While in Figs. 3 and 6 they are inline with each other. The flanges H of Figs. 5 and 8 are not at the outer sides of the tubes C but in line with their central portions. These ribs or flanges are in mutual contact as shown in Fig. 8.

The operation of the boiler will be readily understood. The combustion gases from the grate Gr will strongly heat the water contained in the inner tubes C and such water together with steam developed therein will rise through said tubes to the collector B.

The relatively cool water will return to the lower Water chambers E, being supplied thereto by the descending tubes D. When the upper ends of these tubes D are connected with the collector B, as at the left-hand portion of Fig. 1, the water will pass from said collector downward in a direct path through said tubes D to the water chamber E. On the other hand, when a separate water chamber F is connected with the upper ends of the descending tubes D as at the right-hand portion of Fig. 1, the relatively cool Water from the steam collector B will pass to the main boiler A andthen to the said separate waterehamher F in order to reach the upper ends of the descending tubes D. As I have indicated above, the provision of the separate water chamber F may be preferable in. many cases since it affords a greater opportunity for the boiler scale and other sediment to be carried into the main boiler where such deposits are 'relatively harmless. It will be noted from Fig. 1 that the tubes C, C" are arranged so as to confine a space in communication with all of the smoke fiues J provided in the longitudinal boiler A; in other words, when looking lengthwise of the locomotive, all of said smoke flues will appear between the walls formed by the tubes 0, C, and the hot combustion gases produced in the fire box do not come in contact with the outer sides of the walls formed by said tubes C, C. When the constructions shown in Figs. 3 to 7 are substi tuted for those illustrated by Figs. 1 and 2, the relative arrangement of the smoke flues J to the continuous walls formed by the water tubes on the side of the fire box will still remain the same; that is, all of said smoke flues would debouch into the chamberbetween the two. side walls formed by said water tubes.

Various changes-in the specific forms shown and described may be made within the scope of the claims without departing from 'the' spirit of the invention I claim:

1. A steam boiler having a fire-box and steam generatin tubes located laterally of said fire-box anrf forming a continuous wall,

from said collector but communicating therewith and connected with the upper ends of said descending tubes.

2. In a locomotive, the combination with a longitudinal boiler having a fire box at one end thereof, said boiler having smoke flues "opening into said fire box, of a collector 10-- cated above said fire box,'steam generating tubes located laterally of said fire box and connected with said collector, said steam generating tubes forming the sides of the fire box as continuous walls extending downwardly from said collector and being disposed be- 5 yond the outer limits of the boiler smoke flue inlets so as not to impede the flow of fire gases thereinto, and a set of descending tubes for supplying: relatively cool water to the lower ends of said steam generating tubes, said 10 continuous Walls being located between the heating space and said descending tubes so that the datter will be shielded from the action of the combustion gases.

In testimony whereof I have hereunto set my hand.

PETER QTHOMSEN. 

